1. Field of the Invention
The present invention relates generally to filter devices, and more particularly to a filter device in which the filter element may be changed without interrupting the fluid flow through the device.
2. Description of the Prior Art
There are many types of previously known filter devices. In all filter devices the filter element eventually becomes clogged or dirty and thus requires periodic cleaning or replacement. When replacement of the filter element is required, in one class of previously known filter devices, it has been necessary to stop the fluid flow through the filter device in order to replace the filter element. This type of filter device is disadvantageous in that the fluid system serviced by the filter device must be stopped while the filter element is being replaced.
In a similar class of filter devices, a second, or backup, filter element is provided so that the fluid flow may be diverted through the back up filter element while the other or primary, filter element is being replaced and vice versa. Although with this type of previously known filter devices it is not necessary to stop the fluid flow through the filter device, such filter devices are unduly complex and thus expensive to manufacture.
In still another type of previously known filter devices, a clogged or dirty filter element is removed from the fluid flow and replaced by a clean filter element. The dirty filter element is then automatically cleaned by the filter device and is thus ready to be replaced in the fluid flow when desired. Like the last described class of previously known filter devices, this type of filter device is also complex and expensive to manufacture.